1. Field of the Invention
The present invention relates to a magnetic read/write head, and more particularly, to a method for forming a gap of a planar silicon head which is a planar thin film magnetic head.
2. Description of the Related Art
A planar silicon head, which is used as one type of a magnetic read/write head in a magnetic read/write device such as a hard disk drive, has been of interest because it has a lower inductance than a general inductive head and thus it can be substituted for the inductive head. Existing heads mostly depend on pseudo contact in order to satisfy a frequency demanded. However, the planar silicon head maintains a flying height at about 1.8 .mu.m which is much higher than the pseudo contact and has almost the same performance as the general head depending on the pseudo contact.
A planar thin film magnetic head and method for manufacturing the same are disclosed, for example, in U.S. Pat. No. 4,949,207, issued Aug. 14, 1990 to Jean-Pierre Lazzari, entitled PLANAR STRUCTURE THIN FILM MAGNETIC HEAD. In U.S. Pat. No. 4,949,207, it is disclosed that a recess is etched in a substrate and is filled by a magnetic film. A coil is formed in an insulating film and magnetic contact pads are formed. Two magnetic films are disclosed to be formed in an insulating film and then in a hard film are formed two pole pieces separated by an amagnetic spacer. In U.S. Pat. No. 4,949,207, in order to form a gap of a thin film magnetic head at the top of an insulation layer situated between two separated magnetic layers, the insulation layer (to be etched later on) deposited to form a vertical well for forming the gap is used as a spacer side well, and the two magnetic layers separated by the spacer are formed at the same time. However, since there is a poor affinity between the material of the gap and the material of an upper pole piece, the gap of the planar thin film magnetic head can increase and it can be difficult to form an accurate shape. Moreover, since the two separated magnetic layers are simultaneously formed, the spacer for forming the gap can be curved or broken.
A planar silicon head includes a magnetic yoke having an upper pole piece (UPP), a concentrator, a pillar and a lower pole piece (LPP) formed on a substrate. The material of the magnetic yoke is permalloy (NiFe) of a magnetic material. The pillar of the magnetic yoke is wound with a coil. A read/write gap for reading and writing data is formed between pole tips of the two separated upper pole pieces (UPPs). A diamond-like carbon (DLC) coated layer is formed at the upper portions of the read/write gap and the upper pole pieces (UPPs). The back side of the silicon substrate has head connectors for electrically connecting the head to an external device. Bumps connected to a suspension of an actuator are formed at the head connectors, respectively.
To manufacture the planar silicon head, four processes are typically needed: a drilling process, an electro-plating process, a gap forming process, and a bump process. The drilling process is for drilling holes in the silicon substrate to form an electrode. The electroplating process is for implementing electroplating to form the upper pole piece (UPP), the concentrator, the pillar, the lower pole piece (LPP), etc. The gap forming process is for forming the gap. The bump process is for forming the bumps at the back of the head for the electrical connection of the silicon head.
However, the planar silicon head can still have problems, in that since an oxide spacer is formed at the side well of a thick photoresist and then the permalloy is deposited around the spacer at a time by a permalloy electroplating process to form the upper pole piece (UPP), the spacer can be curved or broken. Furthermore, in that the material of the gap is an oxide layer, the gap can be contaminated by its properties. Also, the width of the gap can be enlarged under typical temperature and humidly, 46.degree. C., 85% for example, and the length thereof, as a result, is not necessarily uniform.
U.S. Pat. No. 4,639,289 to Jean-Pierre Lazzari, entitled PROCESS FOR PRODUCING A MAGNETIC READ-WRITE HEAD AND HEAD OBTAINED BY THIS PROCESS, discloses a first magnetic material film deposited on a support, a groove etched in the first magnetic film which is shaped like a figure eight, and a double coil formed and wound respectively around the two central pole pieces. An insulating material layer is disclosed as being deposited and etched in step form, the step having a side facing the cental channel. A magnetic film is deposited on the thus etched step, and the film is etched so as to only leave a wall perpendicular to the plane of the films. This is followed by the deposition of a magnetic film and then a protective layer, the assembly being divided off so as to expose two pole pieces separated by an air gap.
U.S. Pat. No. 4,837,924 to Jean-Pierre Lazzari, entitled PROCESS FOR THE PRODUCTION OF PLANAR STRUCTURE THIN FILM MAGNETIC HEADS, discloses a process for producing a planar structure thin film magnetic head wherein a recess is etched in a substrate and is filled by a magnetic film. It is disclosed that a coil is formed in an insulating film and magnetic contact pads are formed. Two magnetic films are disclosed as being formed in an insulating film and then in a hard film are formed two pole pieces separated by a magnetic spacer.
U.S. Pat. No. 4,942,490 to Jean-Claude Lehureau, entitled THIN LAYER MAGNETIC READ/WRITE HEAD, discloses a thin layer magnetic read/write head formed on a substrate in such a manner that a first magnetic pole has a flank which forms a first angle with the side of the substrate and a second magnetic pole has a second flank which is substantially parallel to the first flank. The two flanks are disclosed as being separated by a layer of a magnetic material in order to produce a device which can be especially applied to magnetic tape write/read structures.
U.S. Pat. No. 5,090,111 to Jean-Pierre Lazzari, entitled PROCESS FOR PRODUCING A MAGNETIC RECORDING HEAD, discloses a rectangular parallelepiped having a width of approximately 1 micron and a height of several microns, with separation by an amagnetic spacer.
U.S. Pat. No. 5,168,408 to Jean-Pierre Lazzari, entitled MAGNETIC READING AND WRITING HEAD WITH MAGNETORESISTANT ELEMENT, discloses that in order to improve the sensitivity of the head when reading, without excessively reducing its efficiency when writing, the magnetic circuit used is left open. It is disclosed that the reading flux then re-closes, essentially across the magnetoresistant element (MR).
U.S. Pat. No. 5,274,521 to Teiichi Miyauchi et al., entitled PLANAR THIN FILM MAGNETIC HEAD, disclose a planar thin film magnetic head wherein an axis of easy magnetization in the vicinity of a magnetic gap of a magnetic yoke is forcibly made coincident with the direction of a track width by a magnetic field due to current flowing in a conductor layer. Accordingly, even though the track width is small, a high magnetic permeability, low Barkhausen noise and linear responsiveness can be realized to thereby improve the sensitivity, output and linearity. In another aspect, it is disclosed that a throat portion is eliminated from a thin film magnetic core forming a magnetic gap. The thin film magnetic core is disclosed as being configured such that a pair of magnetic members constituting the magnetic core are diverged from the magnetic gap so that a divergent angle .theta., of first opposite side edges of the magnetic members, from a direction of the gap length of the magnetic gap, is set to the range of 30.degree.&lt;=.theta.&lt;=80.degree., and the magnetic members are disclosed as having second opposite side edges extending in substantially parallel to the direction of the gap length of the magnetic gap. Accordingly, it is disclosed even though a track width is reduced less than 10 .mu.m, adjoining crosstalk or off track crosstalk can be avoided to thereby realize low-noise and high quality reproduction and improve the operating characteristics.
U.S. Pat. No. 5,563,754 to Robert G. Gray et al., entitled THIN FILM MAGNETIC HEAD INCLUDING A DURABLE WEAR LAYER AND GAP STRUCTURE, disclose a thin film magnetic head in which a magnetic yoke assembly is built up, layer by layer, atop a substrate using semiconductor thin film techniques. A lower yoke assembly is disclosed as being first fabricated including a lower magnetic layer situated on the substrate and first and second side poles are built up vertically from the ends of the lower magnetic layer. An insulative pedestal surrounded by a frame is formed at the top of the lower yoke assembly and extends above the uppermost lateral plane of the yoke assembly. A diamond-like carbon (DLC) wear layer is deposited atop the pedestal. It is disclosed that first and second pole wells are excavated in the DLC layer so as to expose the first and second side poles therebelow and to form a DLC gap region between the first and second side poles. First and second magnetic poles are then formed in the first and second pole wells, respectively.
U.S. Pat. No. 5,737,825 to Robert G. Gary et al., entitled METHOD OF MAKING THIN FILM MAGNETIC HEAD INCLUDING A DURABLE WEAR LAYER AND GAP STRUCTURE, disclose that a thin film magnetic head is provided in which a magnetic yoke assembly is built up, layer by layer, atop a substrate using semiconductor thin film techniques. A lower yoke assembly is first fabricated including a lower magnetic layer situated on the substrate and first and second side poles are built up vertically from the ends of the lower magnetic layer. An insulative pedestal surrounded by a frame is disclosed as being formed at the top of the lower yoke assembly and extends above the uppermost lateral plane of the yoke assembly. A diamond-like carbon (DLC) wear layer is deposited atop the pedestal. First and second pole wells are disclosed as being excavated in the DLC layer so as to expose the first and second side poles therebelow and to form a DLC gap region between the first and second side poles. First and second magnetic poles are then formed in the first and second pole wells, respectively.
U.S. Pat. No. 4,601,099 to Toyoo Nishiyama, entitled METHOD FOR MANUFACTURING A MAGNETIC HEAD, discloses a magnetic head that is made by forming a first half core having at least two substantially parallel plane surfaces and one lateral surface, the distance between the two plane surfaces being equal to or greater than a predetermined track width fixing one of the two place surfaces of the first half core on part of one plane surface of a nonmagnetic substrate so that the one lateral surface of the first half core meets with the one plane surface of the substrate. A magnetic insulator is deposited to a substantially uniform thickness on the other of the two plane surfaces and the one lateral surface of the first half core and the remaining part of the one plane surface of the substrate, thereby forming a gap spacer, depositing the same material for the first half core to a substantially uniform thickness on the gap spacer film, thereby forming a second half core having a thickness equal to or greater than the predetermined track width, and removing at least part of the gap spacer film lying on the other plane surface of the first half core and part of the second half core lying on the part of the gap spacer film to be removed from the other plane surface of the first half core, thereby forming a magnetic head.
U.S. Pat. No. 5,754,377 to Robert G. Gray et al., entitled THIN FILM MAGNETIC HEAD INCLUDING AN ELEVATED GAP STRUCTURE, disclose a thin film magnetic head in which a magnetic yoke assembly is built up, layer by layer, atop a substrate using semiconductor thin film techniques. A lower yoke assembly is disclosed as being first fabricated including a lower magnetic layer situated on the substrate and first and second side poles are built up vertically from the ends of the lower magnetic layer. An insulative pedestal surrounded by a frame is formed at the top of the lower yoke assembly and extends above the uppermost lateral plane of the yoke assembly. A diamond-like carbon (DLC) wear layer is deposited atop the pedestal. It is disclosed that first and second pole support wells are excavated in the DLC layer so as to expose the first and second side poles therebelow, and further to receive first and second pole supports, respectively, therein. First and second pole extension members are situated on the first and second pole support members, respectively, with a non-magnetic gap region being situated between the first and second pole extension members. A second DLC layer is situated in the same plane as the non-magnetic gap region and the first and second pole extension member. The second DLC layer substantially surrounds the first and second side pole extensions and the gap region. In this manner, the gap region is elevated above the plane of the first and second pole support members and is protected from undesired head wear.
U.S. Pat. No. 5,801,909 to Robert G. Grayetal., entitled THIN FILM MAGNETIC HEAD INCLUDING DURABLE WEAR LAYER AND NON-MAGNETIC GAP STRUCTURES, disclose that a thin film magnetic head is fabricated on a substrate by depositing a seed layer on the substrate. A lower magnetic layer is disclosed as being plated on the substrate in an opening provided in an insulative layer which is deposited on the seed layer. A plurality of magnetic layers are plated at one end of the lower magnetic layer to build-up and form a first side pole by using the above seed layer as a seed. Another plurality of magnetic layers are disclosed as being plated at the other end of the lower magnetic layer to build-up and form a second side pole by using the same seed layer as a seed. The first and second side poles thus formed include upper and lower ends, the lower ends being plated to the ends of the lower magnetic layer. A first upper pole is plated to the upper end of the first side pole and, first upper pole includes a gap end facing the second side pole. It is disclosed that a gap region of nonmagnetic material is deposited adjacent the gap end of the first upper pole. A second upper pole is plated to the upper end of the second side pole and includes a gap end adjacent the gap region. A diamond-like carbon (DLC) frame is fabricated at the uppermost portion of the head surrounding the upper side poles and gap region. It is disclosed that the DLC frame provides both structural integrity to the head and wear protection when the head contacts the media surface.